Apparatus for producing precast monolithic manholes



United States Patent [72] Inventor Joseph F. llerzog 11525 W. Biscayne Canal Road, Miami, Florida 33161 [2]] Appl. No. 734,786 [22] Filed June 5,1968 [45] Patented Nov. 24, 197.0

[54] APPARATUS FOR PRODUCING PRECAST MONOLITHIC MANHOLES 4 Claims, 8 Drawing Figs.

[52] US. Cl 249/65, 249/74, 249/l44, 249/160, 264/294 [51] Int. Cl B28b 7/10, 82% 21/82 [50] Field of Search 249/144, 142, 65, 74, 27, 75, 151, 160, 19; 264/294. 34, 250, 255; 25/1 28D; l8/Rubber Mold Digest [56] References Cited UNITED STATES PATENTS 266,832 10/1882 Johnston 249/75 1,720,503 7/1929 Wickey 249/144x 3,l6l,703 12/1964 Watson 249/19X FOREIGN PATENTS 674,986 7/l952 GreatBritain 249/65 Primary Examiner-Robert D. Baldwin Atr0rney-Salvatore G. Militana ABSTRACT: Apparatus for producing precast monolithic manholes having an outer cylindrical form with an offset portion mounted at the upper end, a lower inner form slidably supported within the outer form by a jack and a main inner form centered on the lower form; the spaces between the forms forming the cylindrical and tapered portions ofthe manhole and upon being poured and set, the main inner form is removed and an inflatable member is placed within the upper end of the poured concrete, a closure member positioned on the inflatable member and further concrete is poured in the off set portions to form the base of the manhole.

11 I I! I'III\I III! 11! Patented Nov. 24, 1970 I of 2 Sheet FIG. 4

INVENTOR dOsEFH F. HERZOG FIG?) Patented Nov. 24, 1970 Z of 2 Sheet in, 1 "JEQKKL! a FIG.8

FIG. 5

age 37 APPARATUS FOR PRODUCING PRECAST MONOLITHIC MANHOLES This invention relates to construction products and is more particularly directed to the apparatus for producing reinforced concrete manholes that are monolithic in construction At the present time, all manholes are constructed at the site on the ground or in the hole in the ground in which the manhole is to remain. This requires the services of highly skilled artisans who must first pour a base and then cement'on a sec tion of large diametered concrete pipe or pipes as the body of the manhole. Then a bricklayer must lay brick on the open end to form the tapering neck portion. All of this is time consuming, expensive and requires highly skilled labor. The present invention contemplates the production of a manhole of desired dimensions at a factory and delivering the precast manhole to the site where it is lifted into place and the sewerage pipes connected to it.

Therefore a principal object of the present invention is to provide a precast reinforced concrete manhole that is monolithic in construction and relatively inexpensive in cost.

A further object of the present invention is to provide apparatus for producing reinforced concrete manholes that may be adjusted for making manholes of different heights.

A still further object of the present invention is to provide apparatus for producing precast concrete manholes that does away with the need for highly skilled labor and cuts down to a minimum on the time that would normally be necessary to build the manhole at the site oferection.

With these and other objects in view, the invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming a part of this specification, with the understanding, however, that the invention is not confined to any strict conformity with the showing of the drawings but may be changed or modified so long as such changes or modifications mark no material departure from the salient features of the invention as expressed in the appended claims.

In the drawings:

FIG. 1 is a perspective view of a manhole produced by my apparatus;

FIG. 2 is a cross-sectional view of my apparatus showing the first step in the manufacture ofthe manhole;

FIG. 3 is a similar view illustrating the second step of manufacture;

FlG. 4 is a cross-sectional view taken along the line 44 of FIG. 3;

FIG. 5 is a cross-sectional view of my apparatus showing the third step of manufacture;

FIG. 6 is a similar view illustrating the final step ofmanufacture; and

FIGS. 7 and 8 are side elevational views of the inner forms.

Referring to the drawings wherein like numerals are used to designate similar parts throughout the several views the numeral l0 refers to a monolithic reinforced concrete manhole which was precast in and removed from my manhole production form -F- the subject matter of the present patent application.

The manhole 10 itself is ofconventional design consisting of a hollow cylindrical portion 11 with a conical upper portion 12 terminating in an opening 13, all of which are mounted on a base portion 14 with pipe openings 15 formed in the lower portion ofthe wall ofthe cylindrical member 11.

The manhole production form -F- which is capable of producing the manhole 10 of monolithic reinforced concrete construction consists of a large hollow cylindrical member 16 mounted on a base 17 on which a hydraulic or pneumatic jack 18 is positioned. The cylindrical member 16 which operates as the outer form is provided with an opening 19 at its base portion in order to insert the jack 18 in position and permit manipulation ofits handle 20.

Mounted on the top edge of the cylindrical member 16 is a flange portion 21 extending horizontally about whose peripheral edge there is a vertically disposed flange 22, the

flanges 21 and 22 support the concrete that'formthe base portion 14 of the manhole 10, There are bores 23 formed on opposite sides of the wall 16 adjacent the flange 21.

There is supported by the hydraulic jack 18 a solid cylindrical member 25 which isa part of the inner form and is slidably fitted inside the hollow cylindrical member 16. The upper surface of the cylinder 25 is provided with tapering sidewalls 26 and at the center of the cylinder 25 there is a cylindrical cavity 27 which serves as a form centering means as is explained hereinafter.

Within the cylindrical form 16 is an inner form 30 consisting of cylindrical sidewall 31, 'a base 32 at one end with tapering sidewalls 33 at the other end having a centering cylinder 34 extending therefrom and centrally mounted about the axis of the cylinder 30. The inner'form 30 determines the size of the manhole 10 to be produced, there being a different inner form 30 for each manhole 10 of different lengths. The solid or support cylinder 25 is adjusted vertically as to its position in the outer form 16 by the pneumatic or hydraulic jack 18, the sole requirement being that the base 32 of the inner form 30 would be in approximate coplanar relation with the horizontal flange 21.

In the normal production ofa manhole 10 by the use of my invention, the centering form 25 is mounted on the hydraulic jack 18 and the latter is operated to position the centering form 25 at the proper height in the form 16 as determined by the size of the manhole 10 to be manufacturcd. The steel rods 40 that constitute the reinforcing structure of the manhole 10 are shaped to conform with that ofthe manhole 10 is placed in the form 16 while the proper sized inner form 30 is selected and inserted into the outer form 16 with the centering cylinder 34 received in the cavity 27. The centering form 25 is then adjusted as to its height in the outer form 16 by operation of the hydraulic jack 18 by its handle 20 until the base 32 is in approximate coplanar relation with the horizontal flange 21.. Then block members 35 are inserted between the forms 16 and 30 and secured therein by bolts 36 extending through the bores 23 formed in the outer form 16. Concrete is then poured in the space between the forms 16. 25 and 30, about the rein forcing rods 40. The concrete is vibrated but no concrete is placed in the place above the base member 32 at this time.

When the concrete thus poured is set, the inner form 30 is removed from the partially formed manhole 10 by being pulled out by any lifting device (not shown) engaging the eye bolt 37 that is fastened to the base 32 of the inner form 30. Then aninflatable member 41 such as an inner tire tube is placed at the upper inner portion of the newly formed concrete wall 11 and inflated to engage the inner sidewalls 11. A circular piece of plywood 42 or the like is placed on the inflated member 41 which then acts as a support for concrete reinforcing rods 43 then placed in the space above the flange 21. Lifting loops 44 of wire construction are also interengaged with reinforcing rods 43 placed within the flange 22 prior to the pouring of the concrete that forms the base 14. Since the reinforcing rods 40 extend above the side wall ll and are in terengaged with the reinforcing rods 43 when concrete is poured therein becomes set, the manhole 10 thus formed becomes monolithic in construction.

After a relatively short period when the concrete last poured has become set, the hydraulic jack is operated to lift the manhole 10 out of the outer form 16 as shown by P16. 6, Prior to this, the bolts 36 are first removed, freeing the block members 35 so as to permit the newly formed manhole 10 to slide upwardly. A lifting device (not shown) is then utilized to remove the manhole 10 from the outer form 16. The manhole 10 is then turned right side up, the inflatable member 41 is deflated and removed along with the board 42 and the blocks 35 are removed from the sidewall 11. After the proper curing period has elapsed, the manhole 10 is ready to be placed in the ground, A lifting device engages the lifting loops 44 and lowers the manhole 10 into the hole in the earth. All that need be done is then to cement the sewer pipe connections to the openings 15 formed in the manhole 10 and place a cover over the manhole opening 13.

I claim:

1. Apparatus for producing precast concrete monolithic manholes comprising an outer hollow form having offset portions for forming the base of said manhole mounted at the upper end of said outer form, a lower inner form supported in said outer form, said lower inner form being tapered to form the tapered neck portion of the manhole, a main inner form mounted within said outer form and in spaced relation thereto, said main inner form having an upper end portion in proximity of said offse't portion of said outer form and a lower tapered portion spaced from said tapered portion of said lower inner form, centering means mounted on said main inner form and cooperating with said lower inner form for centering said main inner form and for forming an opening in the top of said manhole, engagement means adapted to facilitate removing said main inner form after concrete has been poured between said forms up to said offset portions, an expandable member adapted to engage the upper inner surfaces of said poured concrete, a closure member adapted to rest on said expandable support member for supporting further concrete poured in said offset portions. 9

2. The structure as recited by claim 3 wherein all of said forms being cylindrical in shape and said centering means comprises a cylindrical member received by a cavity in said lower inner form.

3. The structure as recited by claim 1 and jack means mounted below said lower inner form for adjustably positioning said lower inner form in said outer form.

4. The structure as recited by claim 3 wherein said outer form is provided with opposed openings adjacent said offset portions for supporting block members in said spaces between said outer and said main inner forms. 

